The Direct Contact Condensation of Steam in a Pool at Low Mass Flux

Abstract

The direct contact condensation of steam at low mass flux (in the chugging region) and the pressure oscillation induced by steam condensation were investigated and analyzed. During the experiment, the steam was discharged into a square subcooled water pool in the horizontal direction. The main experimental parameters were the steam mass flux in the range of 10–80 kg/m2·s and the subcooled water temperature in the range of 30–80°C. Also, two different nozzles (5/8, 6/8 inch) were used. In the chugging region, the high pressure pulses were generated with relatively low frequency. The frequency was little affected by the subcooled water temperature, but increased with increasing steam mass flux. A critical value of steam mass flux was found where the pressure pulse generation rate increased suddenly. This critical value for the 5/8 inch nozzle was found to be lower than that for the 6/8 inch nozzle. The pressure pulse was observed to be generated on the occurrence of sudden condensation of the steam bubble which was detached from the nozzle exit by the necking phenomenon.